Oceanologia No. 44 (2) / 02


Invited paper



Invited paper

Metal pollutants and radionuclides in the Baltic Sea - an overview
Oceanologia 2002, no 44(2), pp. 129-178

Piotr Szefer
Department of Food Sciences, Medical University of Gdańsk, Hallera 107, PL-80-416 Gdańsk; pszef@farmacja.amg.gda.pl

Keywords: metals, metalloids, radionuclides, Baltic Sea, biomonitors, chemical balance

Manuscript received 21 May 2002, accepted 24 May 2002.
This overview presents in detail the state of knowledge of the abilities of various components of the Baltic Sea environment to accumulate trace elements and radionuclides. Particular components of the Baltic ecosystem (abiotic and biotic) are considered as potential monitors of pollutants. The use of seaweeds, e.g. Fucus vesiculosus or Zostera marina is recommended, also molluscs, e.g. Mytilus edulis, for biomonitoring surveys of metal pollutants and radionuclides in the Baltic Sea. However, several requirements need to be met if results are to be reliable. Since metal levels and radionuclide activities in the growing tips of F. vesiculosus reflect exclusively the levels of their dissolved species in the ambient seawater, this alga is very useful for monitoring dissolved species of metal pollutants and radioisotopes in the Baltic ecosystem. In contrast, M. edulis, a filter feeder is an appropriate tool for monitoring trace elements occurring in both chemical forms, i.e. dissolved and suspended species. Therefore, full information on the bioavailability and toxicity of heavy metals (depending on their chemical speciation) as pollutants of the Baltic Sea can be obtained if at least two biomonitoring organisms are applied simultaneously, e.g. F. vesiculosus and M. edulis. Moreover, the data matrix can be interpreted more accurately if not only trace element but also macroelement concentrations (Ca, Mg, Na, K) in these two representatives of Baltic phyto- and zoobenthos are taken into consideration; this point requires special attention. Two coastal species of fish, i.e. Zoarces viviparus and Perca fluviatilis, are good biomonitors of metallic contaminants, so their use as sentinels is recommended. The budgets of chemical elements and the ecological status of the Baltic Sea are presented. Several "black spots", e.g. large estuaries and seaport towns, heavily polluted by trace elements, are identified in the Baltic Sea and other enclosed seas such the Mediterranean and the Black Seas. Of these seas, the Baltic is the most heavily loaded with trace elements and organic pollutants. The overview identifies gaps in our environmental knowledge of the Baltic Sea, and sets out possible priorities, key areas or strategies for future research.
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Conformal mapping of the Gulf of Gdańsk onto a canonical domain
Oceanologia 2002, no 44(2), pp. 179-207

Paweł P. Cześnik, Wlodzimierz J. Prosnak
Institute of Oceanology, Polish Academy of Sciences, Powstańców Warszawy 55, PL-81-712 Sopot, Poland; czesiek@iopan.gda.pl

Keywords: shoreline, conformal mapping, domain of solution, computational domain, inversion, Schwarz-Christoffel function, inverse of a function

Manuscript received 7 February 2002, reviewed 15 April 2002, accepted 8 May 2002.
The paper deals with the conformal mapping of a plane, finite, simply connected domain, representing the southern segment of the Gulf of Gdańsk, enclosed from the North by a parallel, tangential to Cape Rozewie. The segment contains the Hel Peninsula.
The method of double decomposition, presented in Prosnak & Cześnik (2001), is applied to the transformation of such an original domain onto a canonical one, which consists of two separate unit discs.
The first decomposition concerns the domain which is split into two adjacent subdomains by means of a segment of a straight line.
The second decomposition involves two holomorphic functions, each one mapping a subdomain onto a separate disc. The decomposition consists in replacing the function by a sequence of simple ones, so that the mapping is performed step-wise. Each sequence starts with the Schwarz-Christoffel function, the last step consisting in an inversion that transforms an infinite circular domain onto a disc.
The data for the problem is contained in the Annex, and is represented by two sets of rectangular coordinates defining consecutive discrete points of the contours bounding the subdomains.
The solution to the problem consists of:
- two sets of functions, consecutively transforming each of the subdomains;
- the numerical values of the parameters of these functions;
- a set of figures illustrating the consecutive transformations.
The accuracy of the first, and of the penultimate transformation are given, because only in the case of these two functions do the unknown coefficients have to be determined by means of a suitable iterative process. The coefficients of all the remaining functions are evaluated from exact formulae.
It should be recalled that the depth of the Gulf of Gdańsk varies considerably - from a few to 110 metres - the gradients of the bottom being rather large. Therefore, the domain of the solution for any mathematical problem describing the hydrodynamical phenomena occurring in the Gulf is usually taken to be three-dimensional. Nevertheless, the paper deals with the transformation of the free surface of the Gulf, assumed as plane. It should be emphasized that this assumption does not mean that the whole domain of the solution has to be regarded as plane.

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Two models for absorption by coloured dissolved organic matter (CDOM)
Oceanologia 2002, no 44(2), pp. 209-241

Jill N. Schwarz
Remote Sensing Technology Institute, German Aerospace Centre, Rutherfordstr. 2, 12489 Berlin, Germany;

Piotr Kowalczuk & Sławomir Kaczmarek
Institute of Oceanology, PAS, Powstańców Warszawy 55, 81-712 Sopot, Poland, P.O. Box 68

Glenn F. Cota
Center for Coastal Physical Oceanography, Old Dominion University 768W 52nd Street, Norfolk, VA 23508, USA

B. Greg Mitchell & Mati Kahru
Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0218, USA
Francisco P. Chavez
Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95039-9644, USA

Alex Cunningham & David McKee
Dept. Physics & Applied Physics, University of Strathclyde, 107 Rottenrow, Glasgow, G4 0NG, U.K.

Peter Gege
Remote Sensing Technology Institute, German Aerospace Centre, Oberpfaffenhofen, 82234 Wessling, Germany

Motoaki Kishino
RIKEN- The Institute of Physical and Chemical Research, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan

David A. Phinney
Bigelow Laboratory for Ocean Sciences, 180 McKown Point Road, P.O. Box 475, West Boothbay Harbor, ME 04575, USA

Robin Raine
Martin Ryan Marine Science Institute, National University of Ireland, Galway, Ireland

Keywords: CDOM, Gelbstoff, ocean colour, UV absorption

Manuscript received 26 March 2002, reviewed 30 April 2002, accepted 6 May 2002.
The standard exponential model for CDOM absorption has been applied to data from diverse waters. Absorption at 440 nm (ag440) ranged between close to zero and 10 m-1, and the slope of the semilogarithmic absorption spectrum over a minimum range of 400 to 440 nm (s440) ranged between < 0.01 and 0.04 nm-1. No relationship was found between ag440 or s440 and salinity. Except in the southern Baltic, s440 was found to have a broad distribution (0.0165 ± 0.0035), suggesting that it should be introduced as an additional variable in bio-optical models when ag440 is large. An alternative model for CDOM absorption was applied to available high quality UV-visible absorption spectra from the Wisla river (Poland). This model assumes that the CDOM absorption spectrum comprises distinct Gaussian absorption bands in the UV, similar to those of benzene. Five bands were fit to the data. The mean central energy of all bands was higher in early summer (E~7.2, 6.6, 6.4, 6.2 and 5.5 eV or 172, 188, 194, 200 and 226 nm) than in winter. The higher energy bands were found to decay in both height and width with increasing salinity, while lower energy bands broadened with increasing salinity. s440 was found to be correlated with shape parameters of the bands centred at 6.4 and 5.5 eV. While the exponential model is convenient for optical modelling and remote sensing applications, these results suggest that the Gaussian model offers a deeper understanding of chemical interactions affecting CDOM molecular structure.
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An overview of the theta - S correlations in Fram Strait based on the MIZEX 84 data
Oceanologia 2002, no 44(2), pp. 243-272

Paweł Schlichtholz,1Marie-Noëlle Houssais2
1Institute of Oceanology, Polish Academy of Sciences, Powstańców Warszawy 55, PL-81-712 Sopot, Poland; schlicht@iopan.gda.pl
2Laboratoire d'Océanographie Dynamique et de Climatologie, UMR7617 CNRS/IRD/Université Pierre et Marie Curie, 4, place Jussieu, 75005 Paris, France

Keywords: water masses, Fram Strait, Aarctic Mediterranean

Manuscript received 18 February 2002, reviewed 9 May 2002, accepted 22 May 2002.
The water masses in Fram Strait have been analyzed on the basis of hydrographic casts taken in summer 1984 during the MIZEX 84 experiment. In particular, theta-S diagrams for 16 areas, each 5o in longitude and 1o in latitude, covering the strait from 77oN to 81oN are used to characterize the water masses and discuss their possible origin. Near the surface, the East Greenland Polar Front clearly separates the lighter, cold and fresh Polar Water (PW) from the heavier, warm and saline Atlantic Water (AW). In the upper ocean, the data show a large spreading of the temperature maximum in the theta-S space associated with different modes of the AW recirculating southward below the PW. Two geographically distinct salinity minima are found in the intermediate layer below the AW. The denser one, in the Boreas Basin, is a feature typical of the Arctic Intermediate Water (AIW) formed by winter convection to the south of the strait, while the lighter one is sandwiched in the Arctic Ocean outflow between the AW layer and the Upper Polar Deep Water (UPDW) characterized by a downward salinity increase. In the deep layer, two salinity maxima are present. The shallower (and warmer) one, associated with the Canadian Basin Deep Water (CBDW), appears all along the East Greenland Slope. A similar but weaker maximum is also found in the southeastern part of the strait. This maximum is perhaps a remnant of the maximum in the East Greenland Current after it has been recirculated back to the strait around the cyclonic gyres of the Nordic Seas. The deeper one appears typically as a near-bottom salinity jump characteristic of the Eurasian Basin Deep Water (EBDW). The jump is found in two distinct areas of the strait, to the north-west in the Lena Trough and to the south-east in the rift valley of the Knipovich Ridge. The maximum in the former area should have been advected from the Arctic Ocean below the CBDW, while the maximum in the latter area might have originated from haline convection on the adjacent shelves. Some EBDW is trapped in the Molloy Deep over a denser water with salinity decreasing down to the bottom and temperature in the range of the Greenland Sea Deep Water (GSDW).
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Stranded Zostera marina L. vs wrack fauna community interactions on a Baltic sandy beach (Hel, Poland): a short-term pilot study.
Part I. Driftline effects of fragmented detritivory, leaching and decay rates

Oceanologia 2002, no 44(2), pp. 273-286

Marcin F. Jędrzejczak
Department of Environmental Chemistry and Ecotoxicology, Faculty of Chemistry, University of Gdańsk, Jana III Sobieskiego 18/19, PL-80-952 Gdańsk, Poland; humbak@idea.net.pl

Keywords: litterbags, decomposition, Zostera marina, sandy beach

Manuscript received 25 March 2002, reviewed 6 May 2002, accepted 15 May 2002.
The effects of the beach community structure of macro- and meiofauna on the process of beach wrack decay were investigated by means of a simple field colonisation experiment in a temperate, fine quartz sediment, sandy beach at the end of the Hel Peninsula in Poland. 1260 replicate litterbags of three mesh sizes (12 mm, 0.5 mm, 48 µm) containing fresh wrack were used to assess the role of faunal and non-faunal components in the breakdown of stranded Zostera marina. Wrack breakdown was determined during a three-year field study.
This paper presents the first part of the results of this field experiment, which refer to the effects of fragmentation detritivory, leaching and decay rates. Material was lost from the bags at a rapid rate, with only 22-32% of the original dry mass remaining after 27 days in the field. This degradation was not directly related to the faunal succession of the eelgrass tissue, which proceeded in two distinct phases throughout the study period. Exclusion of macrofauna from the wrack by the use of finer-mesh litterbags (< 1 mm) had no appreciable effect on the rate of dry matter loss. Microbial decay, and abiotic leaching and fragmentation are probably the major causes of seagrass weight loss from the litterbags.

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The absorption of yellow substance in the Baltic Sea
Oceanologia 2002, no 44(2), pp. 287-288

Piotr Kowalczuk
Institute of Oceanology, Polish Academy of Sciences, Powstańców Warszawy 55, PL-81-712 Sopot, Poland; piotr@iopan.gda.pl

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